Failure to deliver an adequate dose of hemodialysis is a major factor contributing to the high mortality rates observed among hemodialysis patients in the United States. Efforts to improve this situation are limited by the tools available to quantify and troubleshoot hemodialysis dose delivery. Currently there is no inexpensive, reliable screening device on the market that simultaneously monitors the four major parameters that influence hemodialysis adequacy: dialyzer clearance, fiber bundle volume (FBV), true delivered blood flow, and access recirculation. Transonic Systems, Inc. proposes to address this need through the development of a Hemodialysis Adequecy Meter (HDAM). Phase I of the subject application demonstrated the feasibility of using ultrasound dilution technology to make accurate and reproducible measurements of FBV and clearance. During Phase II, we will add out two established measurement methods for delivered blood flow and access recirculation to develop a prototype HDAM. This prototype will be used to perform a multicenter controlled clinical trial of the efficacy of the device. Data from the tril will be used in measurement method optimization. Following FDA clearance, Transonic Systems will proceed to market with the HDAM as a new standard of quality dialysis care. PROPOSED COMMERCIAL APPLICATION: The Transonic Hemodialysis Adequacy Meter will be the only technology capable of fully assessing dialysis adequacy. This technology will improve hemodialysis outcomes, reduce management costs, and improve the quality of life for hemodialysis patients. A low cost, portable device will be successfully marketable in every hemodialysis center and ICU.